Cerebellar defects affect the part of the brain called the cerebellum, which controls muscle coordination and balance. Damage to the cerebellum can cause a lack of control over muscle movement during voluntary movement such as walking (ataxia). Other symptoms vary based on the cause of the defect. Cerebellar defects can occur for different reasons, including: congenital (birth) defects, nutritional deficiencies, infections, toxins, drugs, trauma, multiple sclerosis, metabolic and endocrine disorders, and genetic defects. These defects can be diagnosed using blood tests, MRI tests, and EEGs or EMGs (tests that measure electrical activity). Treatment varies on a case-by-case basis, and is typically focused on treating the underlying issue that is causing the defect. Symptoms are also treated, for example ataxia can be managed through physical therapy.